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HURRICANE GERT DISCUSSION NUMBER 11
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT MON SEP 13 1999
SATELLITE LOOPS DURING THE EVENING SHOWED A BURSTING PATTERN
BEGINNING ON THE NORTH SIDE OF THE EYE WITH THE CIRRUS SPREADING OUT
OVER THE EYE...OBSCURING IT. SATELLITE T-NUMBERS REMAIN THE SAME AS
THE PREVIOUS PACKAGE...4.5 FROM BOTH MIAMI AND SAB. THEREFORE..THE
WINDS REMAIN AT 75 KNOTS.
SHIPS...NOW SEES A SOMEWHAT MORE HOSTILE UPPER LEVEL ENVIRONMENT AT
48 HOURS AND BEYOND AND NOW INTENSIFIES GERT TO ONLY 99 KNOTS.
SINCE THE GFDL MODEL STILL WANTS TO INTENSIFY THE SYSTEM TO OVER 100
KNOTS THE INTENSITY FORECAST WILL REMAIN THE SAME AS THE PREVIOUS
PACKAGE.
BECAUSE OF THE BURSTING PATTERN THERE IS SOME UNCERTAINTY IN THE
INITIAL POSITION AND IT APPEARS THAT THE SYSTEM HAS SLOWED. THE
INITIAL MOTION IS NOW 280/14. A SUBTROPICAL RIDGE TO THE NORTH OF
THE HURRICANE CONTINUES TO GUIDE THE SYSTEM TOWARD THE WEST.
THEREFORE A CONTINUED WESTWARD TRACK IS EXPECTED THROUGH 72 HOURS.
THIS IS CONSISTENT WITH THE TRACK MODELS. THE OFFICIAL FORECAST IS
SIMILAR TO THE PREVIOUS PACKAGE.
JARVINEN
FORECAST POSITIONS AND MAX WINDS
INITIAL 14/0300Z 16.3N 42.7W 75 KTS
12HR VT 14/1200Z 16.6N 44.9W 85 KTS
24HR VT 15/0000Z 17.1N 47.9W 90 KTS
36HR VT 15/1200Z 17.5N 51.1W 95 KTS
48HR VT 16/0000Z 17.9N 53.9W 100 KTS
72HR VT 17/0000Z 18.5N 59.0W 105 KTS
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